Disk harrow with disk gangs spaced longitudinally and overlapped transversely to form a ridge-free center

ABSTRACT

A disk harrow having a forwardly diverging pair of front disk gangs, the innermost disks of which are spaced longitudinally and overlapped transversely to form a ridge-free center furrow as the harrow is advanced forwardly, and a rearwardly diverging pair of rear disk gangs, the innermost disks of which are positioned adjacent to the opposite sidewalls of the center furrow formed by the front disks and spaced longitudinally to deflect soil into and thereby fill the furrow first from one side and then from the other as the harrow is advanced. The front pair of gangs are mounted on the harrow frame to yield inwardly upon striking a stump, rock, or similar obstruction, and the rear pair of gangs are mounted on the frame to yield outwardly upon striking such an obstruction.

United States Patent 1 Tsuchiya et al.

[ 1 3,734,199 51 May 22,1973

[75] Inventors: William Sadayuki Tsuchiya; Thomas Burton Adams, Jr.,both of Moline,

Ill.

[73] Assignee: Deere & Company, Moline, Ill.

[22] Filed: Feb. 8, 1971 [21] App1.No.: 113,456

3,213,946 10/1965 Carrick ..l72/551 1,364,943 l/1921 McAdam......172/587 1,247,017 11/1917 Sharp ..l72/595 Primary Examiner-Robert E.Pulfrey Assistant ExaminerC. W. Hanor Attorney-H. Vincent l-larsha,Harold M. Knoth, William A. Murray, John M. Nolan and John O. Hayes [57]ABSTRACT A disk harrow having a forwardly diverging pair of front diskgangs, the innermost disks of which are spaced longitudinally andoverlapped transversely to form a ridge-free center furrow as the harrowis advanced forwardly, and a rearwardly diverging pair of rear diskgangs, the innermost disks of which are positioned adjacent to theopposite sidewalls of the center furrow formed by the front disks andspaced longitudinally to deflect soil into and thereby fill the furrowfirst from one side and then from the other as the harrow is advanced.The front pair of gangs are mounted on the harrow frame to yieldinwardly upon striking a stump, rock, or similar obstruction, and therear pair of gangs are mounted on the frame to yield outwardly uponstriking such an obstruction.

4 Claims, 7 Drawing Figures PATENTEB $184,199

sum 1 OF 2 III vINVENTORS W. S. TSUCHIYA T. B. ADAMS Jr.

Y Lu 0 L14,

ATTORNEY PATENTED WY 2 21975 SHiIET 2 OF 2 FIG.5

FIG. 3

FIG.6

FIG.4

INVENTORS W. S. SUCHIYA T. B. ADAMS Jr,

FIG.7

ATTORNEY DISK HARROW WITH DISK GANGS SPACED LONGITUDINALLY ANDOVERLAPPED TRANSVERSELY TO FORM A RIDGE-FREE CENTER BACKGROUND OF THEINVENTION The present invention relates generally to disk harrows, andmore particularly to a disk harrow having front and rear pairs of angleddisk gangs arranged in such a manner as to produce a smooth, ridge-freesoil pattern.

In accordance with conventional tandem disk harrow design, thelongitudinal axes of the forward pair of disk gangs converge rearwardlyand intersect on the foreand-aft centerline of the implement, while thelongitudinal axes of the rear pair of disk gangs converge forwardly andalso intersect on the fore-and-aft centerline of the implement. Inoperation, the inwardly concave disks comprising the front gangs thusdeflect soil outwardly and form a pair of center voids or furrows, whilethe outwardly concave disks comprising the rear gangs deflect the soilback inwardly and fill the furrows left by the front disks. Since aminimum clearance must be maintained between the innermost disks on thefront pair of gangs, a ridge of untilled soil is necessarily leftbetween the furrows formed by these disks. The problems created by theexistence of such a ridge are aggravated by the action of the innermostdisks on the rear pair of gangs in filling the center furrows. Sincethese disks are positioned directly across from each other they act tosimultaneously deflect the soil forming the outer walls of the furrowsinwardly, and as the soil from both sides collides it tends to form in amound or ridge along the centerline of the harrow. The mound or ridge ofsoil thus resulting from the combined action of the inner disks on thefront and rear gangs may cause subsequent planting problems andencourage soil erosion. Although the uncut ridge left by the front diskscan be eliminated by mounting a separate cultivator or middlebreakerattachment on the center of the implement between the front and reargangs, this increases the cost of the implement and represents only apartial solution to the problem.

SUMMARYOF THE INVENTION According to the present invention, this problemassociated with tandem disk harrows of conventional design is eliminatedby arranging the gangs on the implement frame in such a manner that theinnermost disks on the front and rear pairs of gangs are spacedforeand-aft, and the innermost disks on the front pair overlaptransversely. The innermost disk on the rearwardly spaced front gang ispositioned to ride partially within the furrow formed by the innermostdisk on the forward front gang and partially in the untilled soilforming one wall thereof. This arrangement of the front gangs serves toeliminate the ridge of untilled soil left by the front gangs on tandemharrows of conventional design. As a result of the longitudinally spacedarrangement of the rear pair of gangs, soil is deflected back into thecenter furrow or void first from one side thereof and then from theother, thus eliminating the collision of soil and resultant ridgeformation which occurs in the operation of conventional tandem disks.The soil pattern produced by a harrow constructed in accordance with thepresent invention is thus smooth and ridge-free.

The longitudinally spaced relationship of the front gangs, in additionto the advantages already mentioned, permits the gangs to be mounted onthe frame for relative inward movement. Such relative inward movement ofthe front gangs is not possible in conventional disks due to theproximity of the inner ends of the gangs. The front pair of gangs,according to the invention, are mounted on their respective gang framesto move inwardly against the biasing force of a spring upon striking anobstruction such as a rock or stump. In a like manner, the rear pair ofgangs are mounted on their respective frames to move outwardly uponstriking such an obstruction.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment of theinvention will be described in conjunction with the accompanyingdrawings in which:

FIG. 1 is a plan view of a disk harrow constructed in accordance withthe principles of the invention;

FIG. 2 is a fragmentary view of the harrow illustrating the positionalrelationship of the innermost disks on the front and rear pairs of diskgangs, and their action on the soil as the harrow is advanced forwardly;

FIG. 3 is an enlarged cross-sectional view taken along the line 3-3 ofFIG. 2;

FIG. 4 is an enlarged cross-sectional view taken along the line 4-4 ofFIG. 2;

FIG. 5 is an enlarged cross-sectional view taken along the line 5-5 ofFIG. 2;

FIG. 6 is an enlarged cross-sectional view taken along the line 6-6 ofFIG. 2; and

FIG. 7 is a fragmentary, enlarged elevation view taken along the line7-7 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, thebarrow includes a generally rectangular frame structure ll0 composed ofright and left,.longitudinally extending side rails 12 and 14,respectively, interconnected at their fore-and-aft ends by transversecross members 16 and 18, respectively. A triangular plate member 20reinforces each corner of the frame. The frame further includes alongitudinal member 19 extending along the centerline thereof betweenthe cross members 16 and 18. A T-shaped hitch structure 22 is mounted onthe forward side of the front cross member 16 for swinging movementabout a transverse axis, the hitch including a longitudinally extendingtongue member 24 provided at its forward end with a U-shaped clevis 26for attachment to the drawbar of a tractor, and fixed at its rearwardend to the center of a transverse member 28. Inner and outer straps 30and 32, respectively, are fixed to each end of the member 28, each pairof straps extending rearwardly on either side of a bracket 34 fixed tothe forward side of the frame cross member 16. A pin 36 pivotally mountseach pair of straps 30 and 32 on their adjacent bracket 34 to define theswinging axis of the hitch 32.

The frame 10 is supported by a pair of right and left ground wheels 38and 40, respectively, rotatably mounted on the opposite ends of atransverse axle 42 outwardly of the frame side members 12 and 14,respectively. The axle 42 is moved vertically relative to the frame 10,to raise and lower the latter relative to the ground, by means of anextensible and retractable hydraulic cylinder 44. Each end of the axle42 is connected through a conventional linkage 46 to the opposite endsof a rockshaft 48 rotatably mounted on frame members 12 and 14 inbearings 50. The cylinder 44 acts between a bracket 52 on the right sideof the longitudinal center frame member 19 and a radially extending arm54 on the underneath side of the rockshaft 48 to rotate the later and,through the medium of the linkages 46, raise and lower the wheels 38 and40 relative to the frame 10. As the rockshaft 48 is rotated, alongitudinal link 56 interconnecting an arm 58 on the shaft 48 with theupper end of a leaf spring assembly 60 mounted on and extending upwardlyfrom the rear side of the hitch member 28, acts to swing the hitchstructure 22 about the transverse axis defined by the pins 36 andcorrespondingly raise and lower the clevis 26 relative to the frame,whereby the clevis is maintained at a constant height relative to theground as the frame is raised and lowered.

Mounted on and extending along the underneath side of the frame are fourdisk gang assemblies 62 arranged in fore-and-aft, respectively forwardlyand rearwardly diverging pairs. Each gang assembly 62 comprises aplurality of dished, soil-working disks 64 mounted on a frame member 66which, in turn, is mounted in a conventional manner on the longitudinalframe members 12, 14, and 19. It will be noted that the disk gangassemblies 62 comprising each transverse pair are essentially mirrorimages of one another, and that the assemblies 62 comprising eachfore-and-aft pair are identical, though turned end-for-end. Thus, adetailed description of one of the assemblies, shown in FIG. 7, willanalogously apply to the others as well.

Referring to FIG. 7, the disks 64 are mounted on a rod 68 which, inturn, is rotatably supported at each of its ends in bearings 70 and 72.The disks are maintained at equal intervals on the rod 68 by means ofspools or spacers 74. A pair of parallel support arms 76 and 78 arepivotally connected at their lower ends to the bearings 70 and 72, at 80and 82, respectively, and at their upper ends, at 84 and 86,respectively, to brackets 88 and 90 bolted to the underneath side of thegang frame member 66. The disk gang is thus free to swing upwardly andlongitudinally relative to its axis. The arms 76 and 78 areinterconnected by a link 92 extending along and parallel to one side ofthe member 66, in such a manner that the arms 76 and 78 are maintainedin parallel relation and the disk gang is maintained in parallelrelation with the ground.

The gang of disks 64 is biased longitudinally by means of a coil spring94 acting through a pair of links 96 and 98. The links are pivotallyinterconnected at 100 and extend between a pivot bracket 102 bolted toone end of the frame 66, and an arm 104 forming a continuation of thesupport arm 76. A downwardly opening U-shaped member 106 is pivoted atthe point of interconnection of the links 96 and 98 and includes as anintegral part thereof a rod 108 extending vertically from its bightportion. The rod 108 extends through a bracket 110 mounted on the frame66 and receives the coil spring 94 on its upper end portion. The upperend of the rod 108 is threaded to receive a nut 112 which, inconjunction with a washer 114, serves to retain the spring on the rodand adjust the compressive force therein. It will be apparent from thestructure described that the force exerted by the spring 94 tends tobring the links 96 and 98 into alignment, which in turn urges the arm76, and thus the arm 78,

in the clockwise direction as viewed in FIG. 7. Each of the arms 76 and78 is provided with a stop member 116 and 118, respectively, whichengages the underneath side of the frame member 66 to limit the movementof the arms and thus the disk gang. As will be apparent from FIG. 1, thedisk gangs on the front pair of gang assemblies 62 are biased outwardlyagainst their stops and are yieldable inwardly upon striking anobstruction, while the diskgangs on the rear pairs of assemblies 62 arebiased inwardly against their stops and are yieldable outwardly. Theposition of the nut 112 on the upper end of the rod 108 may be alteredto adjust the preload on the spring 94, and thus the amount of forcenecessary to move the gang from its normal stop position.

Reference is now made to FIG. 2 which illustrates the relationshipbetween the innermost disks on the various gang assemblies 62, and FIGS.3 through 6 which, in conjunction with FIG. 2, illustrate the action ofthese disks on the soil as the implement is advanced forwardlytherethrough. It will be noted from FIG. 2 that the innermost disk onthe left front gang, designated 64a, includes a rear edge normallydisposed forwardly of the front edge of the innermost disk 64b on theright front gang. When the left front gang moves transversely inwardlyupon striking an obstruction, the disk 64a thereon is thus free to moveinwardly past the front edge of the disk 64b on the right front gang.Similarly, when the right front gang moves transversely inwardly uponstriking an obstruction, the disk 64b thereon is free to move inwardlypast the rear edge of the disk 64a on the left front gang. The innermostdisk 64a on the left front gang is operable, as the implement isadvanced forwardly, to deflect soil toward the left side of the harrowand thereby form a furrow or void, designated 120L in FIG. 3, having aleft wall 122 composed of tilled soil and a right wall 124 composed ofuntilled soil. The innermost disk 64b on the right front gang, as shownin FIG. 2, is positioned rearwardly of and transversely overlaps thedisk 64a. As the implement is advanced forwardly, the disk 64b thusrides partially within the furrow 120Lformed by the disk 64a andpartially within the untilled soil forming the right wall 124 thereof,and is operable to deflect the soil forming the wall 124 toward theright of the harrow, thereby forming a second furrow or void designated120R. As illustrated in FIG. 4, the two furrows 120L and 120R overlapand combine to form a larger furrow 120 having left and right walls 122and 126, respectively, both walls being composed of tilled soil. Theinnermost disks on the left and right rear gangs, 64c and 64d,respectively, cooperate to fill the furrow 120 formed by the disks 64aand 64b. The disk 64c on the left rear gang is positioned rearwardly andlaterally outwardly of the disk 640 on the left front gang, and adjacentto the left wall 122 of the furrow 120. In operation, as illustrated inFIG. 5, the disk 640 is thus operable to deflect the soil forming thewall 122 back into, and to thereby partially fill, the furrow 120. Thesoil deflected into the furrow 120 by the disk 64c is designated 128 inFIGS. 5 and 6. The disk 64d on the right rear gang is spacedlongitudinally from the disk 640 on the left rear gang and positionedadjacent to the right wall 126 of the furrow 120. The disk 64d is thusoperable to deflect the soil forming the wall 126 back into the alreadypartially filled furrow 120 and thereby completely fill the furrow asillustrated in FIG. 6. The soil deflected into the furrow 120 by thedisk 64d is designated 130 in H6. 6. Since the furrow 120 is filledfirst from the left side and then from the right, the soil from the twosides does not collide as it enters the furrow, but instead flows infreely, leaving a uniform, ridge-free pattern at the rear of the harrow.

We claim:

1. A disk harrow comprising: a mobile frame having first and secondsides; first and second forwardly diverging front gangs of inwardlyconcave soil-working disks on the first and second sides, respectively,of said frame, the innermost disk on said first front gang beingoperative as the harrow is advanced forwardly to deflect soil toward thefirst side of said frame and thereby form a furrow having laterallyopposite, first and second walls of tilled and untilled soil,respectively, and a disk on the inner portion of said second front ganghaving a front edge spaced rearwardly of the rear edge of the innermostdisk on said first front gang, said disk on the inner portion of saidsecond front gang being normally disposed partially in the furrow andpartially in the untilled soil forming the second wall thereof as theharrow is advanced forwardly, said last mentioned disk being operativeto deflect the untilled soil forming the second wall toward the secondside of said frame and thereby widen said furrow; means yieldablymounting said front gangs on said frame for transverse inward movementrelative to each other in response to an abnormal side load imposed onsaid front gangs, the rear edge of the innermost disk on said firstfront gang being movable inwardly from its normal position past thefront edge of the disk on the inner portion of said second front gang,and the front edge of the disk on the inner portion of said second frontgang being movable inwardly from its normal position past the rear edgeof the innermost disk on said first front gang; and first and secondrearwardly diverging rear gangs of outwardly concave soil-working disksmounted on the first and second sides, respectively, of said frame, theinnermost disk on said first rear gang being disposed rearwardly andlaterally outwardly of the innermost disk on said first front gang andadjacent to and outwardly of the first wall of said furrow, saidinnermost disk on said first rear gang being operative as the harrow isadvanced forwardly to deflect the soil forming said first wall inwardlyinto the furrow, and the innermost disk on said second rear gang beingdisposed rearwardly of the innermost disk on said first rear gang andadjacent to and outwardly of the second wall of said furrow, saidinnermost disk on said second rear gang being operative as the harrow isadvanced forwardly to deflect the soil forming said second wall inwardlyinto the furrow.

2. The invention defined in claim 1 wherein said means yieldablymounting said front gangs on said frame comprises support means mountingsaid gangs on said frame for transverse inward and outward movement;stop means acting between said support means and said frame to limit theextent of outward movement of said gangs; and resilient means actingbetween said support means and said frame to bias said gangstransversely outwardly.

3. The invention defined in claim 1 including means yieldably mountingsaid rear gangs on said frame for transverse outward movement relativeto each other in response to an abnormal side load imposed on said reargangs.

4. The invention defined in claim 3 wherein said means yieldablymounting said rear gangs on said frame comprises support means mountingsaid gangs on said frame for transverse inward and outward movement;stop means acting between said support means and said frame to limit theextent of inward movement of said gangs; and resilient means actingbetween said support means and said frame to bias said gangstransversely inwardly.

1. A disk harrow comprising: a mobile frame having first and secondsides; first and second forwardly diverging front gangs of inwardlyconcave soil-working disks on the first and second sides, respectively,of said frame, the innermost disk on said first front gang beingoperative as the harrow is advanced forwardly to defLect soil toward thefirst side of said frame and thereby form a furrow having laterallyopposite, first and second walls of tilled and untilled soil,respectively, and a disk on the inner portion of said second front ganghaving a front edge spaced rearwardly of the rear edge of the innermostdisk on said first front gang, said disk on the inner portion of saidsecond front gang being normally disposed partially in the furrow andpartially in the untilled soil forming the second wall thereof as theharrow is advanced forwardly, said last mentioned disk being operativeto deflect the untilled soil forming the second wall toward the secondside of said frame and thereby widen said furrow; means yieldablymounting said front gangs on said frame for transverse inward movementrelative to each other in response to an abnormal side load imposed onsaid front gangs, the rear edge of the innermost disk on said firstfront gang being movable inwardly from its normal position past thefront edge of the disk on the inner portion of said second front gang,and the front edge of the disk on the inner portion of said second frontgang being movable inwardly from its normal position past the rear edgeof the innermost disk on said first front gang; and first and secondrearwardly diverging rear gangs of outwardly concave soil-working disksmounted on the first and second sides, respectively, of said frame, theinnermost disk on said first rear gang being disposed rearwardly andlaterally outwardly of the innermost disk on said first front gang andadjacent to and outwardly of the first wall of said furrow, saidinnermost disk on said first rear gang being operative as the harrow isadvanced forwardly to deflect the soil forming said first wall inwardlyinto the furrow, and the innermost disk on said second rear gang beingdisposed rearwardly of the innermost disk on said first rear gang andadjacent to and outwardly of the second wall of said furrow, saidinnermost disk on said second rear gang being operative as the harrow isadvanced forwardly to deflect the soil forming said second wall inwardlyinto the furrow.
 2. The invention defined in claim 1 wherein said meansyieldably mounting said front gangs on said frame comprises supportmeans mounting said gangs on said frame for transverse inward andoutward movement; stop means acting between said support means and saidframe to limit the extent of outward movement of said gangs; andresilient means acting between said support means and said frame to biassaid gangs transversely outwardly.
 3. The invention defined in claim 1including means yieldably mounting said rear gangs on said frame fortransverse outward movement relative to each other in response to anabnormal side load imposed on said rear gangs.
 4. The invention definedin claim 3 wherein said means yieldably mounting said rear gangs on saidframe comprises support means mounting said gangs on said frame fortransverse inward and outward movement; stop means acting between saidsupport means and said frame to limit the extent of inward movement ofsaid gangs; and resilient means acting between said support means andsaid frame to bias said gangs transversely inwardly.